I need your help. I've got a check engine light on, which turns out is due to the o2 sensor needing to be replaced. My car passes smog otherwise. I'm flat broke and can't afford the repair. ($450 quote)

I heard that if I disconnect my battery, then reconnect it, it will cause the light to go off long enough to pass the smog. Is this true? Will it work?

I'm planning on getting the item replaced, I just won't be able to do it for a couple of months and I need to get my current reg sticker on my car.

Also, how do I disconnect the battery. I"m COMPLETELY clueless as to car repair/maintenance!

:00000732:

OMG!!!

The battery is the square black thing that sits just behind the front right headlight (when standing in front looking at the vehicle) and you will see it has two round things called battery posts poking up on either side of the battery to which cables will be connected.

Look closely and you will see one battery post will be identified with a '+' mark (positive) and the other post with a '-' (negative).

You remove a battery cable by undoing the cable clamp nut sufficiently enough to slightly swivel the cable connecting clamp and then pull the clamp up and remove it from the battery.

A good thing to remember is to always remove the '-' (negative) cable first to prevent any accidental short occurring, before disconnecting the '+' cable from the battery (voltage spikes caused by 'short' can have a very deleterious effect on the vehicle's engine management computer).

Now disconnecting the battery might achieve what you want however, I'm not sure whether it will or not (have a search through this and other Volvo forums - I'm sure you will find someone else who has experienced this problem).

If your O2 sensors are really shot, then disconnecting the battery will achieve absolutely nothing however, replacing the O2 sensors willy-nilly may not achieve the desired result either as the check engine light (CEL) can be triggered by numerous other faults while the engine is running that the computer registers and stores in it's memory.

My CEL comes on at regular intervals (it seems to me about 300 kms) and I just cancel it at the Diagnostic Control Unit and take no real notice of it. It doesn't appear to have any affect on the running of the vehicle at all.

If all else fails you could purchase an oxygen sensor (it is usually the first one that fails) and install it yourself - it's not all that hard (but then again - if you don't know how to disconnect a battery....)

Some final comments:
(1) perhaps now is the time to invest in something like a Haynes Repair Manual for the 850 (it's better than having nothing)
(2) if you are struggling to come up with $450 to keep this car on the road then maybe, just maybe, this isn't the vehicle for you as they can be expensive to maintain.

Good luck!

+1

Its the SPIRIT and WILLINGNESS that counts, ...right?
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Everyone has to begin from somewhere...









*whispering*
Errr, Greek, am i right or what?
Hey get up from the floor, man.
Hey bro, dont let them see you laughing like that, bro...
That's wicked.
:D